gh_new_canvas

Create a fresh empty Grasshopper canvas.

SERVERRhino SOURCEeasehee/rhino-mcp

High RISK CLASS

Category Execute

Parameters 00 required

Recommended Rate-limitedsee the rule below

Registry record Grade F, identity unverified Pull the record →

This record as markdown: /tools/easehee-rhino-mcp/gh-new-canvas.md

WHAT IT DOES

What gh_new_canvas does on Rhino

AI agents invoke gh_new_canvas to trigger actions in Rhino. What it does depends on the arguments the agent supplies, and its effects often reach beyond the immediate call: builds kicked off, notifications sent, workflows started.

RISK

Why gh_new_canvas is rated High

gh_new_canvas triggers real processes with real consequences. An agent gone sideways doesn't fire it once. It starts dozens of builds, sends mass notifications, or burns through compute before anyone looks up.

Attacks that exploit this kind of access

RECOMMENDED RULE

The rule that runs gh_new_canvas safely

PolicyLayer is an MCP gateway: it sits between your AI agents and Rhino, and checks every tool call against a rule you set before the call runs. Nothing changes on the server itself. For gh_new_canvas, this is the rule to start with:

gh_new_canvas Rate-limited

gh_new_canvas stays usable, but rate-capped: a runaway agent can't fire it dozens of times a minute. Everything else on the server is denied unless you say otherwise.

View as policy code

policy.json

{
  "version": "1",
  "default": "deny",
  "tools": {
    "gh_new_canvas": {
      "limits": [
        {
          "counter": "gh_new_canvas_rate",
          "window": "minute",
          "max": 10,
          "scope": "grant"
        }
      ]
    }
  }
}

RATE-LIMIT THIS TOOL → Instant setup, no code required.

The button opens the PolicyLayer dashboard: create your workspace, connect Rhino, apply this rule, and every gh_new_canvas call is checked against it from then on.

FAQ

Questions about gh_new_canvas

What does the gh_new_canvas tool do? +

Create a fresh empty Grasshopper canvas. It is categorised as a Execute tool in the Rhino MCP Server, which means it can trigger actions or run processes. Use rate limits and argument validation.

How do I enforce a policy on gh_new_canvas? +

Register the Rhino MCP server in PolicyLayer and add a rule for gh_new_canvas: allow, deny, rate-limit, or require approval. Point your MCP client at the PolicyLayer proxy URL and the rule is enforced on every call, before it reaches Rhino. Nothing to install.

What risk level is gh_new_canvas? +

gh_new_canvas is a Execute tool with high risk. Execute tools should be rate-limited and have argument validation enabled.

Can I rate-limit gh_new_canvas? +

Yes. Add a rate_limit block to the gh_new_canvas rule in your PolicyLayer policy. For example, setting max: 10 and window: 60 limits the tool to 10 calls per minute. Rate limits are tracked per agent session and reset automatically.

How do I block gh_new_canvas completely? +

Set action: deny in the PolicyLayer policy for gh_new_canvas. The AI agent will receive a policy violation error and cannot call the tool. You can also include a reason field to explain why the tool is blocked.

What MCP server provides gh_new_canvas? +

gh_new_canvas is provided by the Rhino MCP server (easehee/rhino-mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.

KEEP EXPLORING

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